Blake Lively has commented on “how terrifying” the foiled Taylor Swift Vienna concert terror attack was. The 34-year-old Grammy winner made the decision to cancel her three Austrian gigs after authorities uncovered a planned terror attack at the Ernst Happel Stadium and Blake – who is married to ‘Deadpool and Wolverine’ star Ryan Reynolds – is among those to react to the ordeal. The 36-year-old actress, who has been to see the ‘Shake It Off’ singer on her ‘Eras Tour’, told Access Hollywood: “Oh, my gosh. I mean, how terrifying. “But thank goodness that they are completely on top of that.” Offi…